Thank you for the help. Maybe the Kindle simply runs out of memory (doh

). Could swap help? Almost tempted to try out with a loopback image in /mnt/us and see if /bin/swapon and /bin/swapoff might be a good idea to call on demand - e.g. start it, run the app that is crashing all the time, afterwards turn back off.
Unless there really is a memory leak, and no amount of virtual ram will help.